Stove for burning liquid hydrocarbon fuel



Nov. 1, 1955 c. BRAMMING 2,722,271

STOVE FOR BURNING LIQUID HYDROCARBON FUEL.

Filed March 11, 1952 INVENTOR.

M UQW ATTORNEYS.

United States Patent 'Ofilice 2,722,271 Patented Nov. 1, 1955 STGVE FOR BURNING LIQUID 'HYDROCARBON FUEL Carl Bramming, Nashville, Tenn., assignor to Aladdin Industries, Incorporated, Nashville, Tenn., a corporation of Illinois Application March 11, 1952, 'Serial No. 275,935

1 Claim. (Cl. 158-35) This invention relates to stoves burning liquid hydrocarbon fuel. In particular, it concerns a stove, well adapted for portable use, in which means are provided for self-generation of fuel pressure and wherein novel means are provided for regulating the rate of flow of fuel.

It is desirable in stoves of the type under consideration, particularly those which are to be moved about from place to place, that the fuel tank remain reasonably cool during operation, and that the supply of fuel to the burner be controlled to maintain an even flame size and temperature.

In the stove of the present invention, both those ends are achieved, and the major objects of the invention may accordingly be stated to be the provision of a stove wherein self-generation of fuel pressure is achieved while maintaining a cool fuel tank and, at the same time, maintaining effective control of fuel supply and substantially constant flame size and temperature.

I have illustrated in the accompanying drawing an illustrative embodiment of my invention. In the drawing, Fig. 1 shows, in vertical sectional view, a portable .stove embodying my invention. Fig. 2 is a horizontal sectional view taken through the wick tube along the line 22 of Fig. 1. Fig. 3 is a vertical sectional view, taken along the line .3-3 of Fig. 1, showing a portion of the valve housing of my invention in a plane at right angles to the sectional plane of Fig. 1.

My portable stove is mounted upon and supported by a fuel tank preferably provided with a 'base flange 11 and a bottom member 12 joined to the vertical sides of tank 10 above flange 11 and having a curved surface presenting a contour generally convex as viewed from below the tank. This type of construction is familiar in oilcans, etc., and the curved bottom element can be pressed upward by the user to create a temporary increase in vapor pressure within the tank, to discharge some of the liquid fuel into a pre-heating bowl, just as oil can be forced from an oil can by pressing the bottom thereof.

Centrally of the top portion of tank 10 a cylindrical recess 13 is provided, a portion of the bottom of which is relieved to form a central aperture 14. An annular member 15, provided with internal threads, is suitably secured within recess 13 as by brazing or force-fitting. A gland or follower member 16 is threadedly received within element and acts to impose sealing pressure on packing gasket 17, which is made of some suitable material such as gasoline-proof synthetic rubber.

A supporting tube 18, made of some material, such as chrome steel, which conducts heat poorly, is held in .position centrally of tank 10 by means of gasket 17. At its upper end, supporting tube 18 carries securely joined thereto, as by shrink-fitting, a hollow plug 19 which serves as supporting means for wick tube 20. Wick tube 20 extends from the valve housing 21, threadedly carried on plug 19, downward through aperture 14 into the interior of tank 10, terminating a short distance above bottom member 12.

The lowermost portion of wick tube 20 is partially closed by a plug member 21a, secured therein by shrink .fitting or other suitable means. Plug 21a contains a small central aperture 23.

From the central lower surface of valve housing 21, comprising the top of the vaporizing chamber, .a .few strands 22 of glass wool are suspended within the interior of wick tube 20, terminating on top of .pl'ug 21a.

Vaporizing chamber 24, into which the upper end of wick tube 20 opens, is connected by means of passage 25 with a starting valve 26, threadedly fitted into a suitable bore in valve housing 21.

Vaporizing chamber 24 is also connected, by means of passage 27, with main fuel control valve 28, received within a suitable bore in valve housing '21 and manually controllable by means of adjustment knob 29. Shaft 31, connecting knob 29 with valve 28, passes externally of the valve chamber through a stufling box comprising packing 32, packing ring 33, gland 34, and follower or look-- ing nut 35. An intermediate zone 36 of the bore containing valve 28 is internally threaded, and the valve member 28 is correspondingly externally threaded to provide a substantial range of movement for the valve when knob 29 is manually rotated.

The innermost end of valve member 28 is tapered along surface 37 to provide a variable area vapor passage between the inlet chamber 38 and the interior chamber 39 of the burner proper. It will be obvious to persons skilled in the art that the degree of communication permitted past surface 37 will depend upon the position of the control valve 28. When the valve is in its innermost position, as shown in Fig. 1, communication between chambers '38 and 39 is entirely out off. As knob 29 is turned and valve member 28 accordingly retracted the area of the passage between the two chambers is increased.

Valve element 28 contains, in its innermost end, a lengthy axial aperture 41 milled to provide a flat side (not shown). Received within axial recess 41 is the elongated arm of a crank member 42, shaped for cooperation with the aforesaid flat side of recess 41 so as to be readily slideable in the axial direction within recess 41 but being incapable of rotation therein.

The inner end of crank member 42 is received within a slot 43 cut in a follower element 44 .slideably movable within chamber 39 in the plane perpendicular to the plane of the section depicted in Fig. 1. (See Fig. 2).

Chamber 39 communicates with burner chamber 45 via a pair of orifices 46, oppositely situated in the wall of chamber 39. A needle 47, mounted on follower 44 and movable therewith, moves back and forth between the orifices 46 when knob 29 is rotated. That is, in one position of knob 29, and of crank 42, needle 47 passes through and blocks off one of the orifices 46, while in the opposite position of crank 42, needle 47 leaves the first-mentioned orifice 46 and enters and blocks off the other. When valve 28 is in its wide-open position, the needle 47 is intermediate the two orifices 46 and does not impede either of them.

The burner chamber 45 is defined by the upper surface of the valve housing 21 and by the inner portion of burner bowl 48, mounted on the upper surface of valve housing 21 but spaced a short distance thereabove to provide a substantially annular air inlet slot 49. The flames leave the burner chamber 45 and enter theupper portion of burner bowl 48 through apertures provided under a pair of tongues 51 stamped out of burner bowl 48 in the area substantially above the orifices 46.

The cooperative action of the burner chamber 45, the tongues 51, and the orifices 46 is to direct the flames around the open portion of burner bowl 48 rather than permitting them to rise; the result is a substantially annular flame distributed more or less uniformly around the open portion of burner bowl 48.

An outer shield member 52 is provided to encase the burner apparatus, and to serve as a support for a grate or pan-supporting spider 53.

Shield member 52 is mounted upon and carried by the pre-heating bowl 54, which surrounds entirely the lower portion of valve housing 21. Starting valve 26, when opened, provides communication between vaporizing chamber 24 and pre-heating bowl 54. It will be understood, of course, that the pro-heating bowl is used only for a few moments at the time the stove si first turned on. At all other times, the starting valve 26 is kept in closed position.

Operation When my stove is first placed into operation, starting valve 26 is opened and some fuel injected into the preheating bowl 54 by pressing the bottom portion 12 of tank 10 in a manner similar to pressing the bottom of an oilcan. As soon as a moderate quantity of fuel (which may be gasoline or other suitable volatile hydrocarbon liquid) has been discharged into preheating bowl 54, starting valve 26 is closed and the pool of fuel in bowl 54 is ignited, preferably by introducing a match into aperture 57 adjacent valve 26.

The fuel in bowl 54 rapidly burns, heating to a relatively high temperature the valve housing 21 and the other parts which comprise the burner apparatus. As the fuel in the pre-heating bowl is consumed, the heat generated by its burning heats the valve housing 21, wick tube 20, and the air in the insulated annular space between wick tube 20 and supporting tube 18. This air, upon being heated, increases its pressure and moves downward into tank 10 via aperture 14, thus raising the vapor pressure within tank 10 and tending to force the liquid fuel therein upward within the interior of wick tube 20.

The liquid fuel passes through the small aperture 23 and rises within wick tube 20, at least in part by capillary action involving the threads of glass wool 22.

I have found that glass wool threads 22 and the superatmospheric air pressure generated by the air within supporting tube 18 cooperate to provide extraordinary uniformity of fuel delivery to the vaporizing chamber 24. If the glass wool threads be omitted the pressure will nevertheless force fuel into the vaporizing chamber, but in the absence of the glass wool, the flow is pulsating rather than uniform.

I have found, in the present stove embodying my invention, that the combination of my novel pressure-generating means and the few strands of glass wool provides a fuelfeeding means which is vastly superior to the wicks found in the prior art.

Upon arriving at the upper portion of wick tube 20, the fuel from tank 10 is vaporized, by reason of the heat in valve housing 21, and, being vaporized, flows through passage 27, past valve 28, and into chamber 39. From chamber 39, the vaporized fuel passes through orifices 46 into the apertures under tongues 51. Meanwhile fresh air for combustion enters through aperture 57 and slot 49 and mixes in chamber 45 with the fuel emerging from orifices 46. The resulting combustible mixture may be lighted, resulting in perfectly blue flames which distribute themselves more or less uniformly around the burner bowl 48.

It will be understood that the important and novel contribution of the needle 47, with its associated mechanism involving follower 44 and crank 42, is to maintain the orifices 46 at all times free from sediment which might otherwise tend to clog them, such as carbon deposit or other contaminating material which sometimes finds its way into the fuel. I have specifically disclosed and claimed that aspect of my invention in my copending application, Serial No. 180,063, filed August 17, 1950. Therefore, while the structure forms an important part of the operating mechanism of my present stove, I have not claimed it as such herein.

I have found that uniformity of flame size and temperature is further improved by making the area of the orifice 23 in plug 21 approximately twice as great as the total area of the two discharge orifices 46.

lt may be noted from Figs. 1 and 2 that I have in the appended drawing shown the glass fibers 22 as being two in number. It is to be understood that I do not limit myself to any particular number of such fibers, since I have found that successful results can be obtained with wicks made up from two to six or more fibers. in most cases, however, two fibers give excellent performance and provide uniform flow of fuel to the burner.

In similar stoves designed heretofore, attempts have been made to supply the liquid fuel to the vaporizing chamber in the valve through a tightly packed wick disposed in a wick tube. This presented numerous obstacles. If too tightly packed the wick would hamper the fuel flow, if too loosely packed, the fuel flowed too freely, but after the wick tube was heated it sometimes happened that the fuel flow was shut off owing to expansion.

While I have in the present application described in considerable detail a particular embodiment of my invention, it is to be understood that that description is illustrative only and that the scope of my invention is to be determined primarily with reference to the appended claim.

I claim:

In a stove for burning liquid hydrocarbon fuel, a fuel tank, a burner disposed thereabove, said burner comprising a valve housing having a vaporizing chamber, a wick tube connecting said chamber to the interior of said tank, a tubular jacket concentric with said wick tube and spaced therefrom to define an annular air passage therebetween, first sealing means for said jacket providing a substantially air-tight seal between the upper end of said jacket and the body of said burner, second sealing means for the lower end of said jacket operative to provide an air-tight seal between the jacket and the fuel tank while providing free communication between said annular passage and the upper portion of said fuel tank, said wick tube extending through the interior of said fuel tank and terminating near the bottom thereof, whereby the heating of air in said annular air passage will increase the vapor pressure within said fuel tank and tend to force liquid fuel upward in said wick tube, said wick tube being provided with a wick extending through the major portion of said tube and comprising a small plurality of individual fibers of glass wool.

References Cited in the file of this patent UNITED STATES PATENTS 688,464 Glud Dec. 10, 1901 712,097 Rosenbrook Oct. 28, 1902 717,795 Baker Jan. 6, 1903 896,110 Hennig Aug. 18, 1908 1,915,141 Wiley June 20, 1933 FOREIGN PATENTS 39,091 Switzerland June 12, 1913 565,717 Great Britain Nov. 13, 1944 

